On Tuesday, January 21, 2020 7:35:03 AM EST Miro Hrončok wrote:
> This is a known thing in gcc 10:
> 
> https://gcc.gnu.org/gcc-10/porting_to.html#common
> 
> "Default to -fno-common
> 
> A common mistake in C is omitting extern when declaring a global variable
> in a header file. If the header is included by several files it results in
> multiple definitions of the same variable. In previous GCC versions this
> error is ignored. GCC 10 defaults to -fno-common, which means a linker
> error will now be reported. To fix this, use extern in header files when
> declaring global variables, and ensure each global is defined in exactly
> one C file. As a workaround, legacy C code can be compiled with -fcommon.
> 
> 
>        int x;  // tentative definition - avoid in header files
> 
>        extern int y;  // correct declaration in a header file"

So, for those of us using F31 as the development / test environment, is there 
a macro that we can add -fno-common to in ~/.rpmmacros without placing it in 
the %__global_compiler_flags in /usr/lib/rpm/redhat/macros ?

Looking for an easy way to reproduce this without modifying root owned files.

-Steve

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